Serious ocular manifestations occur in the majority of AIDS patients ranging from noninfectious background microangiopathy to potentially blinding retinitis due to cytomegalovirus (CMV) infection. This has lead to RFA 88-EY-01, "The Ocular Complications of AIDS", to which two applications have been submitted from this institution: one for a Chairman's Center (Douglas A. Jabs, MD) and one for a Coordinating Center (Curtis L. Meinert, PhD). They represent a joint effort; however, each may stand on its own merits in the review process. The disciplines represented by the senior investigators listed in these proposal include those of ophthalmology, biostatistics, epidemiology, internal medicine, virology, and information systems. The investigators have the experience in multicenter epidemiologic studies needed to collaborate with the National Eye Institute staff in the formation multicenter research group to develop a comprehends set of etiologic and therapeutic studies of the ocular manifestations of AIDS. This will require planning, detailed design, conduct and analysis of a coordinated mix of study designs including clinical trials, cohort, and case-control approaches Initially, three studies are proposed: 1. A randomized clinical trial of ganciclovir therapy for CMV retinitis; 2. A prospective cohort study of the natural history of CMV retinitis in newly diagnosed AIDS patients to determine risk factors for onset and correlates of prognosis for CMV retinitis; 3. A prospective cohort study of the ocular manifestations of HIV infection in individuals who have not yet developed AIDS. A discussion of the overall approach to organization and conduct of these and other possible studies is given. A draft Manual of Operations has been prepared that includes components that will be needed for approved studies. This application is for a Chairman's Center.